The measurement of physical quantities is often performed to determine and understand the behavior of physical phenomena. For example, the measurement of noise and the sources or causes of noise is often performed to understand the physics behind the generation of noise. For example, a measurement may be performed to identify where the noise is coming from.
This type of analysis may be performed in the testing of devices. For example, noise data may be collected for an aircraft engine, such as a jet engine. The noise data collected may be analyzed to determine what components within and exterior to the jet engine contribute to the noise. These different components may also be referred to as component noise sources.
Different structures or components in a jet engine or in the jet exhaust generated by a jet engine may contribute different noises at different frequencies. For example, different surfaces within ducts and inlets of a jet engine may contribute noise during the operation of the jet engine. For example, the high speed exhaust flow of a jet engine may contribute noise during the operation of the engine.
Surfaces may be treated with various compounds or components in an effort to reduce noise. With this type of example, the jet engine may be tested with the different types of surfaces to determine whether a noise contribution from those surfaces is reduced with the different treatments.
Currently, arrays of microphones may be used to collect noise data. This noise data may be processed to produce a “picture” of where the noise is coming from, and to determine the intensity of the radiated noise. In obtaining this data, sound sensor units, such as microphones, may be placed at different locations. With current array designs, hundreds or thousands of array locations are needed to cover all the sound propagation paths formed by connecting hundreds of candidate noise source locations to dozens of measurement points of interest.
A number of different types of microphones have been investigated for use in aeroacoustic applications in which the microphones should satisfy a number of requirements. Microelectromechanical systems (MEMS) microphones are among the latest type of microphones showing promise. However, there is currently no known way to cost-effectively package MEMS sensors that meet the requirements of aeroacoustic applications. Therefore, it may be desirable to have a micro-sensor package and associated method of fabricating the same that takes into account at least some of the issues discussed above, as well as possibly other issues.